This invention relates to an apparatus for supplying fresh or makeup toner to a developer system used in a document reproduction machine, and more particularly, to a toner cartridge adapted to selective dispense a quantity of toner into a developer sump.
In xerographic type reproduction machines, latent electrostatic images of the item being copied or printed are generated on a moving recording member such as a photoreceptor through exposure to the document being copied or in accordance with an image signal input. Prior to exposure, the recording member surface is first charged to a desired potential. Following exposure, the latent electrostatic images at the recording member surface are developed at a developing station which, in typical present day practice, comprises one or more magnetic brushes for bringing a developer, usually a mixture of carrier beads and toner, into developing relation with the recording member and the image thereon. Following this, the developed image is transferred at a transfer station to a copy substrate material such as a sheet of paper. After transfer, any remaining developer is removed from the recording member while the developed image previously transferred to the copy substrate material is fixed to provide a permanent copy or reproduction.
In the course of developing images as described above, the toner portion of the developer mixture is periodically depleted and, to maintain the necessary proportion of toner, fresh toner must be added from time to time. Since machines of this type are normally capable of processing several different size images up to a preset maximum, toner depletion may not be uniform across the width of the developer sump.
Various types of toner re-supply systems are known to the prior art as, for example, the canister or cartridge type shown by U.S. Pat. No. 3,337,072 (Del Vecchio et al.). In the Del Vecchio et al. prior art arrangement, a toner supply canister consisting of relatively rotatable inner and outer concentric tubes, each with a toner dispensing opening are used. The supply of fresh toner is held in the inner tube, and by rotating the inner tube relative to the outer tube, the toner dispensing openings in each are brought into alignment. Another toner dispensing system is shown by U.S. Pat. No. 3,339,807 (Eichorn). There, the toner supply canister, once mounted, rotates to bring the toner dispensing holes opposite a series of openings in a stationary grid. Preparatory to this, a tear away strip, which seals the holes during shipment is first removed.
In U.S. Pat. No. 4,688,926, a toner dispensing arrangement is disclosed in which toner is ejected from a rotating cartridge by a toner ejecting rod/cam drive assembly.
The above prior art dispensing arrangement typically utilize the toner dispenser aligned in a horizontal plane. Another variation wherein the dispensing cartridge is inclined or tilted at some small angle to the horizontal is disclosed in co-pending application U.S. Ser. No. 07/426,348 assigned to the same assignee as the present invention. The arrangement disclosed therein shows the toner being dispensed from a plurality of ports formed along the end of the cartridge which extends along the horizontal. U.S. Pat. No. 4,611,730 to Ikesue also discloses, in FIG. 11, a toner dispensing system with the toner cartridge aligned along a non-horizontal plane, but with a different toner exit aperture network. The advantages of the inclined toner system to the horizontal inclined systems to the horizontal systems is that gravity is used to assist the toner dispensing action resulting in a more efficient system. These systems, however, may not provide optimum toner concentration within the toner cartridge along the crucial dispense areas for certain applications.
The present invention is directed towards a modification to the tilted type dispensing system which enables an on-demand toner dispensing action concentrating the toner disposed at a single exit port of the cartridge. The end of the cartridge dispenser is modified by the addition of an end cap assembly which incorporates a scoop segment which picks up and delivers the toner to be dispensed to a single exit port area of the cartridge. In a preferred embodiment, a cog-wheel/pin arrangement is used to periodically open and close the apertures in communication with the exit port in response to a toner dispense signal. More particularly, the invention relates to a copying/printing machine having a movable recording member on which latent electrostatic images are created, developing means for developing said images with toner, and transfer means for transferring developed images to a copy substrate material, said developing means including a developer housing adjacent said recording member with means in said housing to bring developer from a sump in said housing into developing relation with said recording member to develop images on said recording member, the combination of:
a) a tube-like cylinder adapted to contain a supply of fresh toner;
b) means supporting said cylinder in spaced relation above said sump, the axis of said cylinder being at an angle with respect to the horizontal;
c) drive means for rotating said cylinder;
d) said cylinder having a toner discharge opening located at the end of the cartridge lying beneath the horizontal,
e) an end cap assembly connected to said end of the cartridge lying beneath the horizontal, said end cap having a scoop element formed therein, said element being a central cavity extending traversely therethrough, said central cavity having a toner entry aperture for introducing toner into said cavity during rotation, and a toner exit aperture at the other end of said cavity, and
means for selectively enabling toner from said exit aperture to be dispensed through said cylinder toner discharge opening.